Laser surgery in general has become an important advancement in the medical profession over the last several years. Lasers are used in numerous surgical procedures. In the field of plastic surgery alone various types of lasers are prominently utilized in performing a variety of procedures. For example, yellow pulsed-dye lasers are used in the removal or lightening of port-wine stain birthmarks, and the Q-switch ruby, Q-switch YAG, and the alexandrite lasers are used to remove decorative and traumatic tattoos, pigmented lesions, and brown patches and spots. Carbon dioxide lasers are used successfully in a surgical procedure to remove warts and skin growths, and argon lasers are used to treat abnormalities that have a proliferation of blood vessels, such as blood blisters, spider blood vessels on the face, strawberry birthmarks, hemangiomas and bulky vascular tumors. Despite this wide variety of laser types and procedures performed, a laser has never been used to harvest a graft of skin.
A skin graft is a patch of healthy skin that is taken from one area of the body, called the donor site, and used to cover another area where skin is missing or damaged. There are three basic types of skin grafts including a split-thickness, a full-thickness, and a composite skin graft. The split-thickness graft is commonly used to treat burn wounds and uses only the layers closest to the surface. The full-thickness graft is used for areas where thicker tissue is desired and post operative wound contracture must be minimized such as jointed areas where maximum elasticity and movement are required. Full thickness grafts include all of the layers of the skin. A composite graft is used for complex reconstructive purposes such as with skin cancer on the nose and includes removing all of the skin layers, fat and sometimes the underlying cartilage from the donor site.
Split thickness skin grafting is one of the most commonly performed surgical procedures. This process involves shaving a sheet of skin including the entire epidermal layer as well as a portion of the dermis. At present in so far as can be determined, only mechanical dermatomes similar to those shown in U.S. Pat. Nos. 4,690,139 to Rosenberg and D322,672 to Brown, for example, have been successfully utilized in harvesting split thickness skin grafts. These mechanical-type dermatomes typically include an oscillating blade driven by a pneumatic or electrical means for cutting the skin.
One critical shortcoming inherent in the use of these prior art devices is the relatively large amount of blood loss resulting from the cutting of the highly vascularized top layers of skin. In addition, post operative weeping from the lymphatic channels in the skin retards the recovery time and further contributes to the prolonged discomfort of the patient at the donor site. These shortcomings are of increased importance in the treatment of burn victims who require extensive grafting procedures.
An additional shortcoming inherent in the use of mechanical dermatomes is the general distortion of and damage to the graft tissue caused by the force of the cutting blade moving through the skin. This distortion often results in both nonuniform sizes and thicknesses of grafts and is greatly increased by the inevitable dulling of the cutting blade. In a worst case scenario, a dull cutting blade can result in the creation of a wound for the patient without the successful harvest of a graft.
Further, all existing mechanical dermatomes harvest generally rectangular grafts only. Since few wounds are rectangular, the surgeon must trim the graft to fit the wound. This creates additional steps for the surgeon, wastes donor skin and contributes to patient morbidity without benefit.
In the majority of skin graft transplant cases, harvested split thickness skin grafts are subsequently meshed to allow the graft to be expanded to cover a larger area. This process minimizes the size and morbidity of the donor site. However, this process again requires additional steps in the surgical procedure and an additional meshing apparatus.
It is contemplated that these shortcomings in the surgical procedure of harvesting and meshing grafts of skin can be alleviated by utilizing a beam of light generated by a laser as the cutting mechanism. Specifically what is needed is an apparatus capable of generating and controlling a laser beam for efficiently cutting, and, if necessary, meshing segments of skin being harvested from a donor body for successfully performing a grafting operation for a recipient.